Electrified Reactive Capture: System and Catalyst Designs

Direct-air capture (DAC) of CO2 often uses alkali hydroxides as sorbent and relies on an energy-intensive thermal CaCO3/Ca(OH)2 step to release CO2 and regenerate the alkali hydroxide. Reactive capture converts the captured CO2 to value-added products while regenerating the captured liquid. Here we introduce the limitation factors of performance in prior electrochemical reactive capture systems. We explore system and catalyst designs to manipulate the mass transfer, maximize CO2 availability and optimize the catalyst's electronic properties. As a result, we report a carbonate-to-syngas system using this reaction-capture approach has a projected energy efficiency of 50% at 200 mA cm–2 when H2 is added to provide 2:1 H2:CO syngas by coupling with a water electrolyzer. Durability studies show 40 h of initial operating stability.